To meet industry needs for electrical power converters which convert AC to DC without injecting large amounts of harmonic currents into the power system, several transformer and converter topologies are available. All require installation of extra equipment and add to the total cost. Preferred methods are those which perform well in practical power systems which incorporate voltage unbalance and preexisting harmonic voltages. Examples of these methods are given by Rosa, Meir, and McMurray. Also powerful techniques in which the 3-phase power is first converted to 9-phase power before processing have been described in the literature of U.S. Pat. Nos. 5,124,904, 5,455,759, and 5,619,407. Equipments using these three patents are in use. However, continual improvements are sought to reduce cost and increase the power rating capability. This invention describes another 3-phase to 9-phase transformer method which reduces cost, and increases feasible power capability of a low voltage auto-connected transformer.